Backlink functionality almost work, but

I managed to find a way to insert hyperlink that relates various files within the same folder. I.e., using Insert->Link->Link To URL

But it has an unpleasant problem: the label that directing to the file must precisely match the file name.
So everytime I use this Link To URL, I have to append to a .tm to make it work. Otherwise the next time I check the file it can not display properly due to absence of “.tm”
Here is an example:

In this pic, if I omit .tm, two thing will happen depends on set up:

  1. if I initially using url link without .tm, then within this file, although I can type math, and save it; next time I enter this file by click, it messes up!
  2. if I manually save the url link file with .tm, it will behavior normal, but it cannot be recognize by the mother document anymore, and the next time I click this url link, it will direct to a plain empty file!

ennnn, I find a way out…
simply use Insert -> Link -> Hyperlink
But now the question is, what is Insert->Link->Link To URL good for?

I think \slink is supposed to be used for “full” hyperlinks, i.e. complete specifications like and you do not have ways to change the way they display. On the other hand \hlink are more flexible and you can choose how they display. Maybe a good thing to do is to search the documentation to see how the two markup are used there. Personally I never use \slink and always \hlink.